Electrodeposition coating composition

ABSTRACT

A positive-type photosensitive electrodeposition coating composition comprising (A) a photosensitive compound having a molecular weight of not more than 6,000 and containing at least one modified quinonediazidesulfone units represented by the following formula (I) ##STR1## wherein R 1  represents ##STR2## R 2  represents a hydrogen atom, an alkyl group, a cycloalkyl group or an alkyl ether group, 
     R 3  represents an alkylene group, a cycloalkylene group or an alkylene ether group, and 
     A represents a carboxylic acid ester linkage, in a molecule and; or a photosensitive compound obtained by reacting a polyfunctional amino compound with o-benzoquinonediazidesulfonic acid chloride or o-naphthoquinonediazidesulfonic acid chloride, and (B) a water-soluble or water-dispersible resin having a salt-forming group. 
     Said composition is suitable for forming a printed wiring photoresist by coating an electrically conductive material-clad laminated plate by electrodeposition to form a smooth film whose portion exposed to actinic rays such as ultraviolet light through a positive photomask can be washed away with a developing solution.

This application is a continuation of application Ser. No. 08/126,732,filed Sep. 27, 1993, which in turn is a continuation of application Ser.No. 07/718,255, filed Jun. 20, 1991, both applications being nowabandoned.

This invention relates to a positive-type photosensitiveelectrodeposition coating composition, and more specifically, to ananionic or cationic electrodeposition coating composition suitable forforming a printed wiring photoresist by coating an electricallyconductive material-clad laminated plate by electrodeposition to form asmooth film whose portion exposed to actinic rays such as ultravioletlight through a positive photomask can be washed away with a developingsolution.

In the prior art, a printed wiring board for use in an integratedcircuit or the like is formed by plating a laminated plate obtained bycladding an insulator with an electrically conductive material such as acopper foil, laminating a photosensitive film, overlaying a photographicnegative on it, exposing the photosensitive film through the negative,removing the unexposed portion, etching away the unnecessaryelectrically conductive material from the circuit pattern, andthereafter removing the photosensitive film on the circuit pattern.Since the photosensitive film is generally as thick as 50 micrometers,the circuit pattern formed by exposure and development is not sharp, andmoreover, it is difficult to laminate the photosensitive film uniformlyto the surface of the electrically conductive material. In particular,it is more difficult to protect the metal on through-hole portions withthe photosensitive film.

A method is also known to form a circuit pattern for printed wiringwhich comprises applying an etching resist ink to a metal-clad laminatedplate having a through-hole portion by screen printing, etching thelaminated plate to remove metal from the non-printed portion, andremoving the resist ink in the printed portion. According to thismethod, it is hard to form a pattern having a thickness of less than 200micrometers with high reliability, the ink is difficult to coat on thethrough-hole portion, and the metal in the through-hole portion isfrequently removed by the etching treatment. To avoid this, it is alsothe practice to embed an organic material in the through-hole portion soas to prevent the metal in the through-hole portion from being removedby the etching treatment, and finally remove the organic material. Thismethod, however, has the defect that the cost of the circuit platefinally obtained is high and the circuit pattern has low sharpness.

As improvements over these prior methods, U.S. Pat. Nos. 4,632,900 and4,673,458 disclose a method which comprises forming a positive-typephotosensitive resin resist on a printed wiring board byelectrodeposition, overlaying a photographic positive on it, exposingthe board through the positive, and removing the exposed portion with anaqueous alkaline solution to form an image. Since according to thismethod, a coating can be formed easily on the through-hole portion byelectrodeposition and the unexposed portion remains as a resist coating,a printed wiring board having excellent resolution can be obtained.

In the above-cited U.S. Pat. No. 4,632,900, polyoxymethylene polymer,o-nitrocarbinol ester, o-nitrophenyl acetal, and aquinonediazidesulfonyl ester of novolak resin are used as the resin inthe resin composition for forming the photosensitive resin resist byelectrodeposition. In U.S. Pat. No. 4,673,458, a resin obtained byesterifying a hydroxyl group contained in an unsaturated monomer with asulfonic acid group contained in naphthoquinone diazidesulfonic acid,and copolymerizing the resulting unsaturated monomer with anotherunsaturated monomer is used as the above resin. However, the formermethod cannot produce a high-density fine pattern circuit board ofsufficient reliability whichever resin may be used. Moreover, since theelectrodeposition paint has insufficient stability, flocculation isliable to occur and tends to cause filter clogging or imperfections onthe coated surface upon long-term running of the electrodeposition bath.In the latter method, a photosensitive naphthoquinone diazide group isintroduced into the resin through a sulfonic acid ester group. Hence,when the electrodeposition is carried out over a long period of time(the turnover of the electrodeposition paint is long), the sulfonic acidester group in the resin is easily hydrolyzed by a hydrolytic substancein the electrodeposition bath such as water, an acid, a base or analcohol to degrade the resin frequently. As a result, the resincomponent flocculates in the electrodeposition bath or precipitates atthe bottom of the bath. This causes filter clogging or greatly variesthe electrodeposition characteristics such as application voltage.Alternatively, abnormal electrodeposition such as pinholing occurs, andthe electrodeposition coating bath becomes difficult to control.Moreover, the coated film formed from the electrodeposition bath haspoor smoothness and alkali developability, and it is impossible toobtain a printed wiring board having excellent resolution.

It is an object of this invention to solve the aforesaid problems in thepreparation of printed wiring boards, and to provide anelectrodeposition coating composition for forming a positivephotoresist, which has excellent sensitiveness to actinic rays such asultraviolet light, can form a developable uniform coated film on thesurface or the through-hole portion of the circuit plate, and can givean electrodeposition coating bath having good stability over a longperiod of time.

According to this invention, there is provided a positive-typephotosensitive electrodeposition coating composition comprising

(A) a photosensitive compound having a molecular weight of not more than6,000 and containing at least one modified quinonediazidesulfonic acidunit represented by the following formula (I) ##STR3## wherein R₁represents ##STR4## R₂ represents a hydrogen atom, an alkyl group, acycloalkyl group or an alkyl ether group,

R₃ represents an alkylene group, a cycloalkylene group or an alkyleneether group, and

A represents a carboxylic acid ester linkage, in a molecule and

(B) a water-soluble or water-dispersible resin having a salt-forminggroup.

The "alkyl group" for R₂ in formula (I) may be linear or branched, andexamples include alkyl groups having 1 to 15 carbon atoms, such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl,isohexyl, 1-methylpentyl, 2-methylpentyl, n-heptyl, 5-methylhexyl,n-octyl, n-nonyl, n-decyl, dodecyl, tridecyl and tetradecyl groups.

Examples of the "cycloalkyl group" include cycloalkyl groups having 3 to8 carbon atoms, such as ##STR5##

Examples of the "alkylether group" include (lower alkyl)-0-(loweralkylene) groups such as ##STR6##

R₂ is preferably a lower alkyl group having 1 to 6 carbon atoms,especially a methyl group.

The "alkylene group" for R₃ may be linear or branched. Examples includealkylene groups having 1 to 8 carbon atoms, such as ##STR7##

Examples of the "cycloalkylene group" include cycloalkylene groupshaving 3 to 8 carbon atoms, such as cyclopropylene, cyclobutylene,cyclohexylene and ##STR8##

Examples of the "alkylene ether group" are (lower alkylene)-0-(loweralkylene) groups such as ##STR9##

R₃ is preferably a linear alkylene group having 2 to 6 carbon atoms.

Moreover, the "carboxylic acid ester linkage" indicated at A includes alinkage represented by --COO--.

The positive-type photosensitive electrodeposition coating compositionof this invention includes anionic or cationic compositions capable offorming a continuous film on an electrically conductive material byelectrodeposition. When the continuous film is exposed, the exposedportion can be washed away with a developing solution.

The compound (A) containing the modified quinonediazidesulfonic acidunits of general formula (I) used as a positive-type photosensitivecomponent can be produced, for example, by the following methods.

First, a hydroxyl-containing quinonediazide compound represented by thefollowing formula ##STR10## wherein R₁, R₂ and R₃ are as defined above,is produced by addition-reaction between quinonediazidesulfonic acidand/or a quinonediazidesulfonyl halide (to be referred to as the"quinonediazide compound") represented by the following formula##STR11## wherein X represents a hydrogen atom or a halogen atom such asCl, F, Br and I, and a hydroxyl-containing amine compound of thefollowing formula ##STR12## wherein R₂ and R₃ are as defined above.

Then, the resulting hydroxyl-containing quinonediazide compound offormula (V) is reacted with a polyacid chloride compound (e.g. anacrylic acid chloride copolymer), or the compound of formula (V) isreacted with an alpha,beta-unsaturated carboxylic acid chloride such asacrylic acid chloride or methacrylic acid chloride at a ratio of 1 molof an acid chloride group per mol of a hydroxyl group, and the resultingmonovinyl compound is copolymerized with an unsaturated group-containingcompound or subjected to Michael addition reaction with an aminogroup-containing compound.

Of the quinonediazide compounds of formula (II) or (III),1,2-benzoquinonediazidesulfonyl chloride and1,2-naphthoquinonediazide-5-sulfonyl chloride are preferred. Examples ofpreferred hydroxyl-containing amine compounds of formula (IV) includeethanolamine, neopentanolamine, 2-hydroxy-2'-aminoethyl ether,2-hydroxy-2'-(amine-propoxy)ethyl ether, N-methylethanolamine,N-ethylethanolamine, N-propylethanolamine, N-methylpropanol amine,N-ethylpropanolamine, and N-propylpropanolamine. Of these,N-methylethanolamine and N-methylpropanolamine are preferred.

The reaction of the quinonediazide compound of formula (II) or (III)with the hydroxyl-containing amine compound of formula (IV) may becarried out in the presence of an inert organic solvent capable ofdissolving or dispersing a mixture of the compound of formula (II) or(III) and the compound of formula (IV) at a temperature of generallyroom temperature to about 80 ° C., preferably room temperature to about60° C., for a period of about 10 minutes to about 60 hours, preferablyabout 1 to 3 hours. The progress of the reaction can be monitored bymeasuring the amine value of the reaction mixture or by an infraredspectrum analysis.

Specific examples of the inert organic solvent that can be used in theabove reaction include dioxanes such as dioxane and dioxolane; ketonessuch as acetone, methyl ethyl ketone and methyl isobutyl ketone; andaromatic hydrocarbons such as benzene, toluene and xylene. Of these, thedioxanes are preferred because they have an excellent ability todissolve the quinonediazidesulfonyl halide and can be easily removed.

The ratio of the compound (II) or (III) and the compound of formula (IV)mixed is not particularly limited. Usually, it is suitable to mix themso that the mole ratio of the --SO₂ X group to the >NH is about 1:1. Inthe above reaction, the --SO₂ X group of the quinonediazide compoundreacts with the >NH group of the hydroxyl-containing amine compoundpreferentially to the OH group. Hence, the main reaction productobtained by this reaction is the hydroxyl-containing quinonediazidecompound represented by formula (V).

Preferred examples of the compound of formula (V) are given below.

In order to trap hydrogen chloride formed during the reaction, forexample, sodium hydroxide, sodium carbonate and an amine of the sametype as used in the addition reaction can be used as required.

Preferred examples of the compound of formula (V) are given below.##STR13##

Examples of the acid chloride compound capable of reacting with thehydroxyl-containing diazide compound of formula (V) include acrylic acidchloride, methacrylic acid chloride, crotonic acid chloride and acopolymer thereof (polyacid chloride compound).

The reaction of the acid chloride compound with the hydroxyl-containingquinonediazide compound of formula (V) to obtain the photosensitivecompound in accordance with this invention can be carried out by mixingthe acid chloride compound with the hydroxyl-containing quinonediazidecompound at a ratio of nearly 1 mol of a hydroxyl group per mol of anacid chloride in the presence of an inert organic solvent if requiredand maintaining the mixture at room temperature for about 1 to 2 hours.The state of the reaction can be monitored by measuring a peakascribable to an acid chloride group in the vicinity of 1,780 cm⁻¹ in aninfrared spectrum analysis. The inert organic solvent that can be usedhere is a solvent selected from ketonic, aliphatic and ethereal organicsolvents which do not cause reaction with the acid chloride compound.

The thus obtained unsaturated group-containing quinonediazide compoundcan be copolymerized with the other unsaturated group-containing monomerby radical polymerization, etc., or reacted with a polyfunctional aminocompound by Michael addition reaction to obtain a final photosensitivecompound. Moreover, the photosensitive compound can also be prepared bypreviously forming the polyacid chloride compound and then adding thehydroxyl-containing quinonediazide compound of formula (V).

The thus obtained photosensitive compound (A) is a compound having in amolecule, 1 or more, preferably on the average, 1.5 or more, andpreferably at most 5 quinonediazidesulfonic acid units represented byformula (I). The molecular weight of the photosensitive compound (A) is6,000 or less, preferably 500 to 5,000. When the molecular weightexceeds 6,000, the compatibility with the water-soluble orwater-dispersible resin (B) tends to decrease, worsening the stabilityof the coating. Meanwhile, the water-soluble or water-dispersible resin(B) having the salt-forming group [to be referred to as a "resin (B)"],used in this invention, includes a resin having a group capable offorming a salt by e.g. neutralization.

Examples of the resin (B) include a carboxyl group-containing acrylicresin, an amino group-containing acrylic resin, an ammonium salt, asulfonium salt-containing acrylic resin, a carboxyl group-containingpolyester resin, an epoxy resin amine adduct and an onium chloride epoxyresin. The acrylic resin is especially preferable from the aspect ofstability of the electrodeposition bath.

Meanwhile, the acrylic resin (B) having the salt-forming group, used inthis invention, includes an acrylic resin having a group capable offorming a salt by neutralization. Examples of the salt-forming groupwhen the composition of this invention is used as an anionicelectrodeposition coating are anion-forming groups such as a carboxylgroup, a sulfonyl group and a phosphoric acid group. Above all, thecarboxyl group is preferable. On the other hand, examples of thesalt-forming group when the composition of this invention is used as acationic electrodeposition coating are cation-forming groups such as anamino group, an ammonium salt group, a sulfonium group and a phosphoniumsalt group.

The acrylic resin (B) can be produced by, for example, polymerizing anunsaturated monomer mixture containing as an essential component thepolymerizable unsaturated monomer having the above salt-forming group bythe usual radical copolymerization method, or polymerising anunsaturated monomer including an epoxy group-containing polymerizableunsaturated monomer in like manner, and then adding the epoxy group inthe resin together with the amino compound or reacting the resultingsubstance with onium salt-forming compounds such as tertiary aminocompounds and acids to form the onium salt.

Regarding the polymerizable unsaturated monomer used to produce theacrylic resin (B), examples of the anion-forming group-containingunsaturated monomer are (meth)acrylic acid, crotonic acid, itaconicacid, itaconic anhydride, maleic acid, maleic anhydride, fumaric acidand 2-hydroxyethyl acrylate acid phosphate. Examples of thecation-forming group-containing unsaturated monomer are aminoethyl(meth)acrylate, N-tert-butylaminoethyl (meth)acrylate,N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate andN,N-dimethylaminobutyl (meth)acrylate.

Examples of the epoxy group-containing unsaturated monomer are glycidyl(meth)acrylate, glycidyl (meth)acrylamide and allylglycidyl ether.

Examples of the other polymerizable unsaturated monomer which isoptionally used are C₁ -C₂₆ alkyl or cycloalkyl esters of acrylic ormethacrylic acid such as methyl (meth)acrylate, ethyl (meth)acrylate,n-butyl (meth)acrylate, i-butyl (meth)acrylate, tert-butyl(meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,lauryl (meth)acrylate and stearyl (meth)acrylate; hydroxyalkyl(meth)acrylates such as 2-hydroxyethyl (meth)acrylate and2-hydroxypropyl (meth)acrylate; acrylamides or methacrylamides such as(meth)acrylamide, N-methyl (meth)acrylamide, diacetoneacrylamide,N-methylol (meth)acrylamide and N-butoxymethylacrylamide; and vinylmonomers such as styrene, vinyl toluene, vinyl propionate,alpha-methylstyrene, vinyl acetate, (meth)acrylonitrile, vinylpropionate, vinyl pivalate and Veoba monomer (a product of ShellChemical Co.).

The copolymerization of the above monomers is normally carried out byreacting a mixture of the above monomers in a suitable organic solventin the presence of a radical-polymerizable initiator such asazobisisobutyronitrile or benzoyl peroxide at a temperature of about 30°to 180° C., preferably about 60° to 120° C., for a period of about 1 to20 hours. Water-soluble organic solvents, especially alcohols andethers, used in electrodeposition paints are suitable as the organicsolvent. Examples include methanol, ethanol, n-propanol, isopropanol,butanol, ethylene glycol, butyl Cellosolve, ethyl Cellosolve, diethyleneglycol, methylcarbitol, ethylene glycol dimethyl ether, and diethyleneglycol dimethyl ether.

The amount of the salt-forming group in the resin (B) of this inventionis generally 0.3 to 4.5 moles, preferably 0.5 to 1.6 moles/kg based onthe total amount of the photosensitive compound (A) and the resin (B).If the amount of the salt-forming group is less than 0.3 mole/kg, it isdifficult to make the resin water-soluble or water-dispersible, and anelectrodeposition coating composition is difficult to prepare from theresin. If, on the other hand, it exceeds 4.5 moles/kg, it is difficultto coat the resulting electrodeposition paint on a substrate.

The resin (B) used in this invention generally may have a number averagemolecular weight of 3,000 to 100,000, preferably 5,000 to 30,000. If thenumber average molecular weight is lower than 3,000, a coated filmprepared from the resin during electrodeposition tends to be broken andfrequently, a uniform coated film cannot be obtained. If, on the otherhand, it is higher than 100,000, the smoothness and levelness of theelectrodeposited film are degraded and the coated surface tends tobecome uneven. Consequently, the resolution of line images tends to bereduced.

In accordance with another embodiment of this invention, thephotosensitive compound (A) can be formed by the reaction of analiphatic, alicyclic or aromatic polyfunctional amino compound having atleast 2, preferably 3 to 4 primary and/or secondary amino groups witho-benzoquinonediazidesulfonic acid chloride oro-naphthoquinonediazidesulfonic acid chloride at a ratio of nearly thesame equivalent as an equivalent of an amine.

The reaction can be performed by maintaining the quinonediazidesulfonicacid chloride and the polyfunctional amino compound in the presence ofan inert organic solvent capable of dissolving or dispersing them at areaction temperature of usually room temperature to about 50° C.,preferably room temperature to 40° C. for about 10 minutes to about 20hours, preferably about 1 to about 3 hours.

Examples of the inert solvent available in the above reaction includedioxanes such as dioxane and dioxolane; ketones such as acetone, methylethyl ketone, and methyl isobutyl ketone; and aromatic hydrocarbons suchas benzene, toluene and xylene. Of these, the dioxanes are preferablebecause they have excellent solubility in quinonediazide sulfonic acidhalide and can easily be removed. Further, to trap hydrogen chlorideformed during the reaction, alkaline compounds such as sodium hydroxideand sodium carbonate may be used.

Examples of the polyfunctional amino compound used in the above reactioninclude ethylenediamine, diethylenetriamine, triethylenetetramine,polyamideamine, phenylenediamine, xylylenediamine, isophoronediamine, apolyamine compound represented by formula R₄ --NH--R₅ --NH--R₅ --NH₂wherein R₄ is an alkyl group having 8 to 18 carbon atoms and R₅ is analkylene group having 2 to 6 carbon atoms, and mixtures thereof.

The thus obtained photosensitive compound (A) contains in a molecule, atleast 1, preferably on the average 1.5 or more, and preferably at most 5quinonediazidesulfonic acid units. The average molecular weight of thephotosensitive compound is usually 6,000 or less, preferably 500 to3,000. When the molecular weight exceeds 3,000, the compatibility withthe water-soluble or water-dispersible resin (B) having the salt-forminggroup tends to decrease, worsening the stability of the coating.

In accordance with still another embodiment of this invention, thewater-soluble or water-dispersible resin (B), having the salt-forminggroup, used in combination with the photosensitive compound (A), can bethe aforesaid water-soluble or water-dispersible resin (B).

A mixing ratio of the photosensitive compound (A) to the resin (B) inthe positive-type photosensitive electrodeposition coating compositionin this invention is not strictly limited, but is generally adjustedsuch that the amount of the quinonediazidesulfonic acid unit containedin the photosensitive compound (A) is 5 to 60 parts by weight,preferably 10 to 50 parts by weight, per 100 parts by weight of theresin (B).

If the amount of the quinonediazidesulfonic acid unit less than 5 partsby weight, the amount of carboxyl given when the formed coating isexposed to light is generally too small, making hard the developmentwith a weak alkali. Meanwhile, if it is larger than 60 parts by weight,the coating tends to be hard and brittle. Consequently, as adhesion tothe substrate is decreased or cracks occur in the coating duringdevelopment and etching, break of the obtained line images is liable tooccur. Moreover, since permeability of actinic energy rays such asultraviolet rays, etc. are decreased, the irradiation dose has to bedisadvantageously as high as 1,000 mj/cm² for pattern formation.

The electrodeposition coating composition in this is obtained such thatwhen the resin (B) contains the anionic group, it is neutralized with anamine or alkali compound and when the resin (B) contains the cationicgroup, it is neutralized with an organic or inorganic acid, and thendispersed or dissolved in water. When the cationic group is a quaternaryammonium salt group, a quaternary phosphonium salt group or a sulfoniumsalt, it can also be dispersed or dissolved in water as such. Examplesof the neutralizing agent used include alkanolamines such asmonoethanolamine, diethanolamine and triethanolamine, alkylamines suchas triethylamine, diethylamine, monoethylamine, diisopropylamine,trimethylamine and diisobutylamine, alkylalkanolamines such asdimethylaminoethanol, alicyclic amines such as cyclohexylamine, alkalimetal hydroxide such as sodium hydroxide and potassium hydroxide,ammonia; and also acids such as acetic acid, lactic acid, hydrochloricacid and phosphoric acid. They may be used either singly or as amixture.

A hydrophilic solvent may be added to the electrodeposition coatingcomposition in order to increase the flowability of thewater-solubilized or water-dispersed electrodeposition paint further.Examples of the hydrophilic solvent are isopropanol, n-butanol,t-butanol, methoxyethanol, ethoxyethanol, butoxyethanol, diethyleneglycol methyl ether, dioxane and tetrahydrofuran. Generally, the amountof the hydrophilic solvent used is desirably not more than 300 parts byweight per 100 parts by weight of the mixture of compound (A) and theresin (B).

To increase the amount of the coating composition coated on thesubstrate, a hydrophobic solvent may also be added to the composition.Examples of the hydrophobic solvent include petroleum solvents such astoluene and xylene, ketones such as methyl ethyl ketone and methylisobutyl ketone, esters such as ethyl acetate and butyl acetate, andhydrophobic alcohols such as 2-ethylhexyl alcohol). Usually, the amountof the hydrophobic solvent is desirably not more than 200 parts byweight per 100 parts by weight of the above mixture.

As required, other resins may be incorporated to adjust the propertiesof the electrodeposited film. It is also possible to add a dye or apigment.

The positive-type photosensitive electrodeposition coating compositionobtained in this invention has the following characteristics, forexample.

(1) The photosensitive compound (A) having higher hydrophobic naturethan the resin (B) is mixed with said resin (B), so that the compound(A) is easily incorporated into the resin particles to reduce theprobability that quinonediazide easily decomposable by bases contactsthe bases. This is safer than in the case of introducing thequinonediazide group into the resin, and the photosensitivity littlechanges in the long-term electrodeposition coating.

(2) The amount of the photosensitive group can easily be adjusted onlyby changing the mixing ratio of the resin (B) to the photosensitivecompound (A). Consequently, the photosensitivity and the resolution ofthe resist film can easily be changed, and the resist composition befreely designed according to the high density of the circuit platepattern and the production line speed.

Production of the printed wiring substrate using the positive-typeelectrodeposition coating composition in this invention is performed asfollows.

In an electrodeposition coating bath (a solids content in the bath: 3 to30% by weight) is dipped a printed wiring substrate (e.g. a copper-cladplate) as an anode in the anionic electrodeposition coating or as acathode in the cationic electrodeposition coating. A DC current of 20 to400 V is passed. The suitable passing time is 30 seconds to 5 minutes.The film thickness is 2 to 100 micrometers, preferably 3 to 20micrometers as a dry film thickness.

After the electrodeposition coating, the coated product is withdrawnfrom the electrodeposition bath, and washed with water, followed byremoving the moisture contained in the electrodeposited film with hotair, etc.

Subsequently, the surface of the thus formed photosensitiveelectrodeposited film is irradiated with actinic rays such asultraviolet rays via a pattern mask (positive). As theortho-quinonediazide compound in the exposed portion becomes acarboxylic acid via a ketene, it is removed by the developing treatmentwith a developer such as an alkali aqueous solution, making it possibleto realize a high resolution.

The actinic light used for exposure in this invention preferably has awavelength of 3000 to 4500 Å. Sources of this light are, for example,solar light, a mercury lamp, a xenone lamp and an arc light. Irradiationof the actinic light is carried out usually in an irradiation dose of 50to 800 mj/cm², preferably 50 to 500 mj/cm².

The developing treatment is carried out by spraying weakly alkalinewater against the surface of the coated film to wash away the exposedportions of the coated film. The weakly alkaline water may be, forexample, sodium hydroxide, potassium hydroxide, sodium metasilicate,sodium carbonate, organic amine or aqueous ammonia, which has pH of 8 to12, and which neutralizes the free carboxylic acid in the coated film tomake it water-soluble.

The metal portion (non-circuit portion) exposed on the substrate by thedevelopment is removed by an ordinary etching treatment using a ferricchloride, copper chloride solution or ammonium chloride/ammonia etchingsolution, for example. Then, the unexposed coated film on the circuitpattern is removed by dissolving with a Cellosolve-type solvent such asethyl Cellosolve and ethyl Cellosolve acetate, an aromatic hydrocarbonsolvent such as toluene and xylene, a ketone-type solvent such as methylethyl ketone and methyl isobutyl ketone, an acetate-type solvent such asethyl acetate and butyl acetate, or a chlorine-type solvent such astrichloroethylene, or also with a sodium hydroxide, potassium hydroxide,sodium carbonate or sodium metasilicate aqueous solution of pH 8 or morein the case of using an anionic electrodeposition paint, or also with anorganic acid such as acetic acid or lactic acid in the case of using acationic electrodeposition paint.

The positive-type photosensitive electrodeposition boating compositioncan be easily coated on a electrically conductive materials such ascopper foil by electrodeposition, and the electrodeposited film is driedto form a uniform photosensitive film. When light is irradiated onto thephotosensitive film through a positive film, the exposed portion changesas described above and is developed with weakly alkaline water. Theunexposed portion can also be removed by dissolving with the solvent,alkali solution (in the case of using the anionic paint) or the acid (inthe case of using the cationic paint). Accordingly, this can supersedeconventional photosensitive films.

The electrodeposition coating composition of this invention isparticularly suitable for the production of a printed circuit boardhaving through-holes. This composition obviates a soldering step unlikethe case of using a photosensitive dry film, and shortens the process ofproducing the printed circuit board. With a photocurable negative-typeelectrodeposition paint, it is difficult to form a cured film onthrough-holes of small diameters. In contrast, since the unexposedportion remains as a resist film in the present invention, thecomposition of this invention is suitable for the production of printedcircuit board having through-holes of a small diameter.

Using the composition in this invention, the printed wiring substratehaving landless through-holes can easily be produced by exposure via acircuit pattern mask designed so as not to shade the light from thethrough-hole portion.

In the positive-type photosensitive electrodeposition coatingcomposition of this invention, the photosensitive material with thequinonediazide group incorporated through the less hydrolyzablesulfonamide or (sulfonimide), a sulfonamide (imide) linkage or acarboxylic acid ester linkage is used. It is higher in hydrophobicnature than the resin (B) used in this invention. When the aqueousdispersion is therefore formed, the photosensitive material isincorporated into the dispersion particles and it is less likely todirectly contact water, amines and acids that expedite hydrolysis.Consequently, it does not happen that agglomeration or precipitation inthe bottom of the bath occurs in the electrodeposition coating bath overa long period of time and a coating voltage greatly changes. Thus, thestability of the electrodeposition coating bath is high, permitting theeasy handling and controlling.

The following Examples illustrate this invention in more detail. Partsand percentages in Examples are all by weight.

Production of an Acrylic Resin Solution 1

    ______________________________________                                                          parts                                                       ______________________________________                                        2-Methoxypropanol   450             I                                         n-Butyl acrylate    692                                                       Styrene             200                                                       Acrylic acid        108             II                                        t-Butylperoxy octoate                                                                              50                                                        2-Methoxypropanol    50                                                                                          III                                       t-Butylperoxy octoate                                                                              10                                                       ______________________________________                                    

The solvent I was charged into a flask and heated to 110° C. The mixtureII was added dropwise at 110° C. for 3 hours, and the temperature waskept at 100° C. for 1 hour. Subsequently, the mixture III was addeddropwise at 110° C. for 1 hour and the temperature of 110° C. wasfurther kept for 2 hours to afford an acrylic resin solution 1 having asolids content of 67%, a number average molecular weight of 11,000 andan acid value of 84.

Production of Acrylic Resin Solutions 2 to 5

In the same manner as in Production Example 1, acrylic resin solutions 2to 5 were produced according to the formulation shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Acrylic Resin Solution                                                                      2        3       4       5                                      ______________________________________                                        Solvent I                                                                     Butyl Celloslve                                                                             450                      400                                    2-Methoxypropanol      300                                                    Methyl diglyme                 450                                            n-Butanol                              100                                    i-Propanol             150                                                    Mixed solution II                                                             n-Butyl acrylate                                                                            643      222             629                                    n-Butyl methacrylate   400     750                                            Methyl methacrylate    200             100                                    2-Hydroxyethyl         50      100                                            methacrylate                                                                  Styrene       200                      200                                    Glycidyl methacrylate                  71                                     t-Butylperoxy octoate          80                                             Azobisisobutyro-                                                                            80                                                              nitrile                                                                       Benzoyl peroxide       60              50                                     Dimethylamino-                                                                ethyl methacrylate                                                                          157                                                             Acrylic acid           128     100                                            Methacrylic acid               50                                             Mixed solution III                                                            Butyl Cellosolve                                                                            50                       50                                     Dimethyl diglyme               50                                             i-Propanol             50                                                     t-Butylperoxy octoate          5                                              Azobisisobutyro-                                                                            10                                                              nitrile                                                                       Benzoyl peroxide       5               10                                     Reaction temperature                                                                        100° C.                                                                         100° C.                                                                        120° C.                                                                        100° C.                         Properties                                                                    Solids content                                                                              67%      67%     67%     67%                                    Number average                                                                              8,500    12,000  7,000   14,000                                 molecular weight                                                              Acid value    --       100     110     --                                     Amine value   56       --      --      --                                     ______________________________________                                    

Production of an Acrylic Resin Solution 6

A flask was charged with 1,550 parts of the acrylic resin solution 5obtained in Production Example 5, and heated at 40° C. While keeping thetemperature at 40° C., a mixed solution of 44.5 parts ofdimethylaminoethanol and 30 parts of acetic acid was added dropwise overthe course of 30 minutes, and the mixture was maintained at 60° C. for 5hours. There resulted an acrylic resin solution 6 having a solidscontent of 66% and a quaternary ammonium salt content of 0.46 mole/kg.

Production of an Acrylic Resin Solution 7

A flask was charged with 100 parts of the acrylic resin solution 4, anda solution of 18.7 parts of 1,2-naphthoquinonediazide-5-sulfonylchloride in 360 parts of acetone was added thereto. While stirring themixture at 30° C. 10 parts of triethylamine was added dropwise over thecourse of 1 hour. After the resulting mixture was maintained at 30° C.for 2 hours, the reaction product was added dropwise to 5,000 parts ofdeionized water which was being stirred, over the course of 1 hour. Theaqueous layer was separated and dried at 40° C. under reduced pressure.Thereafter, 40 parts of dimethyl diglyme was added and dissolved toobtain an acrylic resin solution 7 having a solids content of 67% and anacid value of 89.

Production of a Hydroxyl-containing Ortho-quinonediazide Compound 1

A four-necked flask was charged with 269 parts ofortho-naphthoquinonediazidesulfonyl chloride and 1345 parts of dioxane,and with stirring at room temperature, 150 parts of N-methylethanolaminewas added dropwise over 1 hour. After the dropwise addition, the mixturewas stirred further for about 3 hours. After determining that theabsorption of the amino group near 3300 cm⁻¹ in the IR spectrum of thereaction mixture disappeared, the reaction was terminated.

The resulting solution was put in deionized water, and the quaternaryamine which trapped hydrochloric acid formed during the reaction wasremoved. The product was then extracted with isobutyl acetate, and thesolvent was evaporated. The residue was dried in a dessicator underreduced pressure to give a hydroxyl-containing ortho-quinonediazidecompound 1.

Production of a Hydroxyl-containing Ortho-qinonediazide Compound 2

A four-necked flask was charged with 269 parts ofortho-naphthoquinonediazidesulfonyl chloride and 1345 parts of dioxane,and with stirring at room temperature, 122 parts of monoethanolamine wasadded over the course of 1 hour. After the dropwise addition, themixture was further stirred for about 3 hours, and then worked up as inthe production of the quinonediazide compound 1. As a result, ahydroxyl-containing ortho-quinonediazide compound 2 was obtained.

Production of an Unsaturated Group-containing Ortho-quinonediazideCompound-1 (UQ-1 Compound)

A four-necked flask was charged with 307 parts of thehydroxyl-containing ortho-quinonediazide compound 1 and 500 parts ofdimethyl diglyme, and the mixture was stirred at room temperature. Afterthe hydroxyl-containing ortho-quinonediazide compound 1 was dissolved indimethyl diglyme, 90.5 parts of acrylic acid chloride was added over thecourse of 1 hour, and the mixture was stirred at room temperature for 3hours. Subsequently, after dimethyl diglyme was evaporated to a solidscontent of 60% at 60° C. under reduced pressure, the reaction productwas put in methanol, and the product was precipitated, filtered, andplaced in a vacuum dryer for drying to obtain an unsaturatedgroup-containing orthoquinonediazide compound-1.

Production of an Unsaturated Group-containing Ortho-quinonediazideCompound-2 (UQ-2 Compound)

A four-necked flask was charged with 307 parts of thehydroxyl-containing ortho-quinonediazide compound 1 and 500 parts ofdimethyl diglyme, and the mixture was stirred at room temperature. Afterthe hydroxyl-containing ortho-quinonediazide compound 1 was dissolved indimethyl diglyme, 104.5 parts of methacrylic acid chloride was addedover the course of 1 hour, and the resulting mixture was then stirred atroom temperature for 3 hours. Then, after dimethyl diglyme wasevaporated to a solids content of 60% at 60° C. under reduced pressure,the reaction product was put in methanol, and the product wasprecipitated, filtered, and placed in a vacuum dryer for drying toobtain an unsatured group-containing ortho-quinonediazide compound-2.

Production of an Unsaturated Group-containing Ortho-quinonediazideCompound-3 (UQ-3 Compound)

A four-necked flask was charged with 293 parts of a hydroxyl-containingortho-quinonediazide compound-2 and 500 parts of dimethyl diglyme, andthe mixture was stirred at room temperature. After thehydroxyl-containing ortho-quinonediazide compound-2 was dissolved indimethyl diglyme, 90.5 parts of acrylic acid chloride was added over thecourse of 1 hour, and the mixture was then stirred at room temperaturefor 3 hours. Subsequently, after dimethyl diglyme was evaporated to asolids content of 60% at 60° C. under reduced pressure, the reactionproduct was put in methanol, and the product was precipitated, filtered,and placed in a vacuum dryer for drying to obtain an unsaturatedgroup-containing ortho-quinonediazide compound-3.

Production of an Unsaturated Group-containing Ortho-quinonediazideCompound-4 (UQ-4 Compound)

A four-necked flask was charged with 293 parts of thehydroxyl-containing ortho-quinonediazide compound 2 and 500 parts ofdimethyl diglyme, and the mixture was stirred at room temperature. Afterthe hydroxyl-containing ortho-quinonediazide compound 2 was dissolved indimethyl diglyme, 104.5 parts of methacrylic acid chloride was addedover the course of 1 hour, and the mixture was then stirred at roomtemperature for 3 hours. Subsequently, dimethyl-diglyme was evaporatedto a solids content of 60% at 60° C. under reduced pressure, thereaction product was then put in methanol, and the product wasprecipitated, filtered and placed in a vacuum dryer for drying to obtainan unsaturated group-containing ortho-quinonediazide compound-4.

Production of a Photosensitive Compound-1

    ______________________________________                                                            parts                                                     ______________________________________                                        2-Methoxypropanol     600            I                                        n-Butyl acrylate      400                                                     2-Hydroxyethyl acrylate                                                                             239                                                     Unsaturated group-containing                                                                        361                                                     ortho-quinonediazide compound-1                                               Dimethyl diglyme      400            II                                       Azobismethoxydimethyl valero-                                                                        60                                                     nitrile                                                                       tert.-Dodecylmercaptane                                                                              10                                                     Azobismethoxydimethyl valero-                                                                        10                                                     nitrile                              III                                      2-Methoxypropanol      20                                                     ______________________________________                                    

The solvent I was charged in a four-necked flask and heated at 60° C.The mixture II was added dropwise at 60° C. over the course of 3 hoursand maintained at that temperature for 1 hour. Then, the mixture III wasadded dropwise at 60° C. over the course of 1 hour and furthermaintained at 60° C. for 2 hours to obtain a photosensitive compoundhaving a solids content of 50% and a number average molecular weight of3,000.

Production of Photosensitive Compounds-2 to -12

According to the formulation shown in Table 2, photosensive compounds-2to -12 were prepared in the same way as the photosensitive compound-1.

                                      TABLE 2                                     __________________________________________________________________________    Photosensitive compound                                                                         -2  -3  -4  -5  -6  -7  -8  -9  -10 -11 -12                 __________________________________________________________________________    Solvent I                                                                     Buty cellosolve   600     600 600 600 600 600 600 600 600 600                 Methyl diglyme        600                                                     Mixed solution II                                                             n-Butyl acrylate  400 323 400 400 323 400 400 323                                                                           400 400 323                     methyl acrylate   239         225         253         239                     2-Hydroxyethyl acryalte                                                                             239 225     225 253     253 239     239                 Acrylie acid          77          77          77          77                  UQ-1 compound (*1)                                                                              361 361                                                     UQ-2 compound (*1)        375 375 375                                         UQ-3 compound (*1)                    347 347 347                             UQ-4 compound (*1)                                361 361 361                 V-70 (*2)         60  60  60  60  60  60  60  60  60  60  60                  tert-Dodecylmercaptan                                                                           10  10  10  10  10  10  10  10  10  10  10                  Butyl cellosolve  400     400 400     400 400     400 400                     Methyl diglyme        400         400         400         400                 Mixed solution III                                                            Butyl cellosolve  20      20  20      20  20      20  20                      Methyl diglyme        20          20          20          20                  V-70 (*2)         10  10  10  10  10  10  10  10  10  10  10                  Reaction temperature                                                                            60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.                                                                     60° C.       Properties                                                                    Solids content    50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%                 Number average molecular weight                                                                 3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                                                                              3000                Acid value        0   60  0   0   60  0   0   60  0   0   60                  __________________________________________________________________________     *1: UQ Unsaturated groupcontaining naphthoquinonediazide compound             *2: V70 Azobismethoxydimethylvaleronitrile                               

Production of a Photosensitive Compound-13

A four-necked flask was charged with 313 parts of coconut oil-typetriamine (R-82 of KAO)* and 313 parts of dimethyl diglyme and themixture was stirred at room temperature, followed by adding 1,083 partsof the unsaturated group-containing ortho-quinonediazide compound-1 overthe course of 1 hour. Subsequently, the reaction temperature was raisedto 50° C. and stirring was further conducted for 3 hours to obtain 74.2%of a photosensitive compound-13 containing ortho-quinonediazide units.

*containing as a principal component a mixture of C₁₂ H₂₅ --NH--CH₂--CH₂ --CH₂ --NH--CH₂ --CH₂ --CH₂ --NH₂ and C₁₄ H₂₉ --NH--CH₂ --CH₂--CH₂ --NH--CH₂ --CH₂ --CH₂ --NH₂

Production of a Photosensive Compound-14

A four-necked flask was charged with 313 parts of a coconut oil-typetriamine (R-82 of KAO) and 313 parts of dimethyl diglyme, and themixture was stirred at room temperature, followed by adding 1,125 partsof the unsaturated group-containing ortho-quinonediazide compound-2 overthe course of 1 hour. Subsequently, the reaction temperature was raisedto 50° C. and stirring was further conducted for 3 hours to obtain aphotosensitive compound-14 containing 74.2 % of ortho-quinonediazideunits.

Production of a photosensitive compound-15

A four-necked flask was charged with 313 parts of a coconut oil-typetriamine (R-82 of KAO) and 313 parts of dimethyl diglyme, and themixture was stirred at room temperature, followed by adding 1,041 partsof the unsaturated group-containing ortho-quinonediazide compound 1 overthe course of 1 hour. Then, the reaction temperature was raised to 50°C. and stirring was further conducted for 3 hours to obtain aphotosensitive compound-15 containing 74.2% of ortho-quinonediazideunits.

Production of a Photosensitive Compound-16

A four-necked flask was charged with 313 parts of a coconut oil-typetriamine (R-82 of KAO) and 313 parts of dimethyl diglyme, and themixture was stirred at room temperature, followed by adding 1,093 partsof the unsaturated group-containing orthoquinonediazide compound 1.Subsequently, the reaction temperature was raised to 50° C., andstirring was further conducted for 3 hours to obtain a photosensitivecompound-16 containing 74.2% of ortho-quinonediazide units.

Production of a Photosensitive Compound-17

A four-necked flask was charged with 313 parts of dimethyl diglyme, 313parts of a coconut oil-type triamine (R-82 of KAO) and 312 parts ofsodium carbonate. With stirring at room temperature, a solution of 807parts of naphthoquinonediazidesulfonic acid chloride in 4,035 parts ofdioxane was added dropwise over the course of 1 hour. After the additionwas over, stirring continued for about 3 hours. After confirming thatabsorption of the amino group in the vicinity of 3,300 cm⁻¹ in the IRspectrum analysis disappeared, the reaction was finished.

Subsequently, this solution was charged in deionized water, followed byremoving the quaternary amine that trapped hydrochloric acid formedduring the reaction. After the product was extracted with isobutylacetate, the solvent was evaporated, and the residue was put in a vacuumdryer for drying to obtain a photosensitive compound-17.

EXAMPLE 1

Hundred parts of the acrylic resin solution 1 obtained in ProductionExample 1 was mixed with 3.8 parts of triethylamine and 5 parts of butylcarbitol for neutralization. Subsequently, 16.7 parts of thephotosensitive compound 1 was added and they were well mixed. Whilestirring the mixture by a high-speed mixer at a stirring rate of 1,000to 2,000 rpm, 717 parts of deionized water was gradually added to obtaina stable dispersion. Said dispersion had the solids content of 8% and pHof 7.8.

EXAMPLES 2 TO 24 AND COMPARATIVE EXAMPLE 1

In the same way as in Example 1, dispersions were obtained in accordancewith the formulation shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________                  Example                                                                       2  3  4  5  6  7  8  9  10 11 12 13 14 15 16 17                 __________________________________________________________________________    Acrylic resin-1                                                                             100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                Acrylic resin-2                                                               Acrylic resin-3                                                               Acrylic resin-4                                                               Acrylic resin-5                                                               Acrylic resin-6                                                               Acrylic resin-7                                                               Acetic acid                                                                   Triethylamine 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13                 Photosensitive compound-1                                                                   33                                                              Photosensitive compound-2                                                                      33                                                           Photosensitive compound-3                                                                         33                                                        Photosensitive compound-4                                                                            33                                                     Photosensitive compound-5 33                                                  Photosensitive compound-6    33                                               Photosensitive compound-7       33                                            Photosensitive compound-8          33                                         Photosensitive compound-9             33                                      Photosensitive compound-10               33                                   Photosensitive compound-11                  33                                Photosensitive compound-12                     33                             Photosensitive compound-13                        33                          Photosensitive compound-14                           33                       Photosensitive compound-15                              33                    Photosensitive compound-16                                 33                 Photosensitive compound-17                                                    Photosensitive compound-18*                                                   Deionized water                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150                                                                             1150               Bath solids content (%)                                                                     8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8%                 pH            7.2                                                                              7.6                                                                              7.4                                                                              7.4                                                                              7.5                                                                              7.6                                                                              7.2                                                                              7.5                                                                              7.1                                                                              7.4                                                                              7.5                                                                              7.3                                                                              7.6                                                                              7.4                                                                              7.3                                                                              7.5                __________________________________________________________________________                                                          Comparative                              Example                              Example                                  18   19   20    21   22   23    24   1                       __________________________________________________________________________    Acrylic resin-1  100                  100                                     Acrylic resin-2       100                                                     Acrylic resin-3            100                                                Acrylic resin-4                  100                                          Acrylic resin-5                                                               Acrylic resin-6                            100                                Acrylic resin-7                                  100                          Acetic acid           4.5                  4.5                                Triethylamine    13        13    13   13         13   13                      Photosensitive compound-1                                                                           33   33    33   16.5 33                                 Photosensitive compound-2                                                     Photosensitive compound-3                                                     Photosensitive compound-4                                                     Photosensitive compound-5                                                     Photosensitive compound-6                                                     Photosensitive compound-7                                                     Photosensitive compound-8                                                     Photosensitive compound-9                                                     Photosensitive compound-10                                                    Photosensitive compound-11                                                    Photosensitive compound-12                                                    Photosensitive compound-13                                                    Photosensitive compound-14                                                    Photosensitive compound-15                                                    Photosensitive compound-16                                                    Photosensitive compound-17                                                                     16                                                           Photosensitive compound-18*                      15                           Deionized water  1150 1150 1150  1150 1150 1150  1150 1150                    Bath solids content (%)                                                                        8%   8%   8%    8%   8%   8%    8%   8%                      pH               7.2  7.6  7.4   7.4  7.5  7.6   7.2  7.5                     __________________________________________________________________________     *: tri1,2-Naphthoquinonediazide-5-sulfonylester of                            2,3,4trihydroxybenzophenone (solids content 100%, quinonediazidesulfone       units 75.2%)                                                             

A two-sided circuit plate for printed wiring board with a copperthickness of 35 microns obtained by subjecting an insulated plate havingthrough-holes 0.4 mm in diameter to electroless copper plating andelectrolytic copper plating was dipped in the aqueous dispersion of 25°C. obtained in each of Examples 1 to 24 and Comparative Examples 1. Saidplate was used as an anode in each of Examples 1-18, 20-22 and 24, and 2and as a cathode in each of Examples 19 and 23, and was connected withthe opposite pole dipped in the aqueous dispersion. After theelectrodeposition was carried out under fixed electricity passageconditions shown in Table 4, the circuit plate was washed with water anddried at 80° C. for 5 minutes. The electrodeposited films were all freefrom pinholes and had the uniform thickness. The insides of thethrough-holes were completely coated.

These aqueous dispersions were stored at 30° C. for 6 months. As aresult, the appearance remained unchanged in Examples 1 to 24, but inthe dispersions in Comparative Example 1, the precipitation of the resinwas observed.

Moreover, after the dispersions were stored at 30° C. for 6 months, theabove experiment was repeated. As a result, in Examples 1 to 24, thefilms were free from pinholes and had the uniform thickness, and theinsides of the through-holes were completely coated. However, inComparative Example 1, the abnormal resin precipitation was partiallyobserved, the thickness was nonuniform and pinholes occurred around thethrough-holes.

                                      TABLE 4                                     __________________________________________________________________________                                     Film thickness                                                           Film after storage                                       Electrodeposition coating conditions                                                               thickness                                                                          (after 6 months)                             __________________________________________________________________________    Example                                                                        1     Constant current 50 mA/dm.sup.-1 120 seconds                                                       10 μm                                                                            9 μm                                      2     Constant current 50 mA/dm.sup.-1 120                                                                9    9                                            3     Constant current 50 mA/dm.sup.-1 120                                                               10    9                                            4     Constant current 50 mA/dm.sup.-1 180                                                               15   15                                            5     Constant current 50 mA/dm.sup.-1 180                                                               15   14                                            6     Constant current 50 mA/dm.sup.-1 180                                                               14   15                                            7     Constant current 35 mA/dm.sup.-1 120                                                                8    7                                            8     Constant current 35 mA/dm.sup.-1 120                                                                8    9                                            9     Constant current 35 mA/dm.sup.-1 120                                                                8    8                                           10     Constant current 35 mA/dm.sup.-1 180                                                               11   10                                           11     Constant current 35 mA/dm.sup.-1 180                                                               12   12                                           12     Constant current 35 mA/dm.sup.-1 180                                                               12   11                                           13     Constant voltage 600V 120                                                                          11   10                                           14     Constant voltage 600V 120                                                                          10   10                                           15     Constant voltage 600V 120                                                                          11   10                                           16     Constant voltage 600V 100                                                                           8    8                                           17     Constant voltage 600V 100                                                                           8    7                                           18     Constant voltage 600V 100                                                                           8    7                                           19     Constant voltage 400V 120                                                                           8    8                                           20     Constant voltage 400V 120                                                                           8    7                                           21     Constant voltage 400V 120                                                                           8    8                                           22     Constant voltage 400V 100                                                                           7    8                                           23     Constant voltage 400V 100                                                                           7    7                                           24     Constant voltage 400V 100                                                                           7    7                                           Comparative                                                                          Constant current 50 mA/dm.sup.-1 120 seconds                                                       12 μm                                                                           abnormal                                     Example                          precipitation                                __________________________________________________________________________

A positive photomask was closely adhered to the resulting film and bothsurfaces were exposed. Subsequently, development was conducted with 2%sodium metasilicate and 2% sodium carbonate, followed by etching andremoval of the resin film. The resulting circuit patterns were observedby an electron microscope and found to be complete circuit patternshaving a circuit width (conductor width) of 30 micrometers. Theunexposed through-hole portion remained completely without undergoingthe copper etching to secure passage of both surfaces.

Moreover, the same experiment was repeated on the films obtained fromthe baths stored at 30° C. for 6 months. Consequently, in Examples 1-24,the circuit patters were as good as those before storage. However, inComparative Example 1, breakage of the circuit ascribable to theundissolved portion of the film in the exposed portion in thedevelopment, breakage of the circuit due to pinholes and lack of passageof through-holes frequently occured, and good circuit patterns could notbe obtained.

We claim:
 1. A positive-type photosensitive electrodeposition coatingcomposition comprising an admixture of(A) a photosensitive amount of aphotosensitive compound or a photosensitive copolymer having a molecularweight of not more than 3000 and containing at least one modifiedquinonediazidesulfonic acid unit represented by the following formula (I ) ##STR14## wherein R₁ represents ##STR15## R₂ represents a hydrogenatom, an alkyl group, a cycloalkyl group or an alkyl ether group, R₃represents an alkylene group, a cycloalkylene group or an alkylene ethergroup, wherein the unit of the above formula (I) combines directly withthe adjoining carbon atoms of a carboxylic group of a polyacid compoundor an α, β-unsaturated carboxylic acid, said modifiedquinonediazidesulfonic acid unit represented by formula (I) beingobtained by the reaction of a polyacid chloride compound or an α,β-unsaturated carboxylic acid chloride with a hydroxyl-containingquinonediazide compound represented by the following formula ##STR16##wherein R₁, R₂ and R₃ are as defined, and (B) a water-soluble orwater-dispersible acrylic resin having a salt-forming group in amountssufficient to form a coating for said positive-type coating composition.2. The composition of claim 1 in which R₂ is an alkyl group having 1 to6 carbon atoms.
 3. The composition of claim 2 in which R₂ is a methylgroup.
 4. The composition of claim 1 in which R₃ is a linear alkylenegroup having 2 to 6 carbon atoms.
 5. The composition of claim 1 in whichthe hydroxyl-containing quinonediazide compound is selected from thegroup consisting of ##STR17##
 6. The composition of claim 1 in which thephotosensitive compound or the photosensitive copolymer (A) contains 1to 5, on the average, of the modified quinonediazidesulfonic acid unitrepresented by formula (I) in a molecule.
 7. The composition of claim 1in which the water-soluble or water-dispersible acrylic resin (B) has ananionic group selected from the group consisting of a carboxyl group, asulfonyl group and a phosphoric acid group.
 8. The composition of claim1 in which the water-soluble or water-dispersible acrylic resin (B) hasa cationic group selected from the group consisting of an amino group,an ammonium salt group, a sulfonium group and a phosphonium salt group.9. The composition of claim 1 in which the water-soluble orwater-dispersible acrylic resin (B) has 0.3 to 4.5 moles/kg of thesalt-forming group based on the total amount of the photosensitivecompound or the photosensitive copolymer (A) and the water-soluble orwater-dispersible acrylic resin (B).
 10. The composition of claim 1 inwhich the water-soluble or water-dispersible acrylic resin (B) has anumber average molecular weight of 3,000 to 100,000.
 11. The compositionof claim 1 in which a mixing ratio of the photosensitive compound or thephotosensitive copolymer (A) to the water-soluble or water-dispersibleacrylic resin (B) is adjusted such that the amount of thequinonediazidesulfone unit of formula (I) contained in thephotosensitive compound or the photosensitive copolymer (A) is 5 to 60parts by weight, per 100 parts by weight of the water soluble or waterdispersible acrylic resin (B).
 12. The composition of claim 1 whichfurther comprises not more than 300 parts by weight, per 100 parts byweight of the mixture of the compound or the copolymer (A) and thewater-soluble or water-dispersible acrylic resin (B), of a hydrophilicsolvent.
 13. The composition of claim 1 which further comprises not morethan 200 parts by weight, per 100 parts by weight of the mixture of thephotosensitive compound or the copolymer (A) and the water-solubleacrylic resin or water-dispersible resin (B), of a hydrophobic solvent.